Growth mode control for direct-gap core/shell Ge/GeSn nanowire light emission

Meng, Andrew C.; Braun, Michael; Wang, Yanming; Peng, Siying; Tan, Wanliang; Lentz, J. Zach; Xue, Muyu; Pakzad, Anahita; Marshall, A. F.; Harris, James S.; Cai, Wei; McIntyre, Paul C.

doi:10.1016/j.mattod.2020.05.019

Cited by 23 publications

(13 citation statements)

References 40 publications

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“…Core/shell Ge/Ge 1– x Sn x nanowires were grown via a three-step process consisting of gold catalyzed vapor-liquid-solid (VLS) growth along with CVD deposition similar to that previously reported. ,− The deposition system used consisted of a load-locked, lamp-heated, rapid thermal, 8 in. quartz cold wall CVD chamber with a base pressure of approximately 10 –7 Torr.…”

Section: Methodsmentioning

confidence: 99%

“…Investigations of the thermal stability of the native GeSn oxide were performed using samples previously grown and purposefully left to oxidize at room temperature in laboratory air. Samples were left to oxidize for at least 2 months to minimize sample-to-sample variation in oxide thickness. , The samples investigated had Sn compositions in the GeSn shell of 2, 4, 6, and 12 at% as determined via XRD, using a procedure described previously . The growth conditions for these samples are shown in Table S2.…”

Section: In Situ Decomposition Of Native Gesn Oxidementioning

confidence: 99%

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Oxide Decomposition and Sn Surface Segregation on Core/Shell Ge/GeSn Nanowires

Braun

Lentz

Bishnoi

et al. 2022

ACS Appl. Electron. Mater.

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As a direct bandgap Group IV alloy, metastable Ge 1−x Sn x (x > ∼0.1) is an extremely interesting optical and electronic material. Germanium core/germanium-tin coaxial heterostructures offer an opportunity to study Sn surface segregation from Ge 1−x Sn x alloys in the technologically interesting composition range that exceeds the maximum solid solubility of tin in diamond cubic structure germanium. We investigate the annealing characteristics of the germanium-tin surface and native oxide for tin contents in the range of 2 to 12 at% for initial conditions ranging from intentional air exposure to surface oxidefree nanowires. For air-exposed samples, we show the presence of a tin-rich oxide that exhibits a composition dependent temperature for thermal decomposition during postdeposition annealing in the XPS chamber. Across the range of Sn compositions investigated, the decomposition temperatures of tin oxide and germanium oxide were found to be the same, indicating a single-phase oxide in which both components decompose simultaneously. Utilizing nominally air-free transfer of freshly synthesized and rapid thermally annealed Ge/GeSn nanowires, we investigated the effects of hydrogen and vacuum (∼50 mTorr) annealing and show the inhibition of Sn segregation to the GeSn shell surface when a surface oxide forms. Formation of a surface oxide during an anneal inhibits further Sn surface segregation and, compared to hydrogen anneals, permits an approximately 175 °C increase in the annealing temperature window before changes occur in the nanowire surface morphology, thus promoting thermal stability needed for many device fabrication processes.

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Section: Methodsmentioning

confidence: 99%

Section: In Situ Decomposition Of Native Gesn Oxidementioning

confidence: 99%

Oxide Decomposition and Sn Surface Segregation on Core/Shell Ge/GeSn Nanowires

Braun

Lentz

Bishnoi

et al. 2022

ACS Appl. Electron. Mater.

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“…131,132 The impact of Sn content on the lasing line position has also been studied. 133,134 In this section, we will show some studies on the lasing modes from GeSn nanolayers and the parameters on which the lasing line depends, such as the cooling temperature, Sn content percentage, and optical pump power. Many works demonstrated the reduction of dislocations in GeSn materials and carrier connement.…”

Section: Gesn-based Led Devicesmentioning

confidence: 99%

Impact of strain engineering and Sn content on GeSn heterostructured nanomaterials for nanoelectronics and photonic devices

et al. 2022

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“…Recently, CMOS-compatible group-IV materials such as Ge and GeSn have attracted much attention as a gain medium for on-chip lasers operating at wavelengths deep in the infrared relevant to free-space communication and sensing applications [10][11][12][13][14][15] . Particularly, group-IV bottom-up nanowires have the potential to produce the smallest, CMOS-compatible on-chip light sources, thus motivating many researchers to grow high-quality Ge and GeSn [16][17][18][19][20][21][22][23][24][25] . In the last decade, the photoluminescence characteristics of Ge and GeSn nanowires have been unveiled [16][17][18][19][20][21][22][23] .…”

Section: Introductionmentioning

confidence: 99%

“…Particularly, group-IV bottom-up nanowires have the potential to produce the smallest, CMOS-compatible on-chip light sources, thus motivating many researchers to grow high-quality Ge and GeSn [16][17][18][19][20][21][22][23][24][25] . In the last decade, the photoluminescence characteristics of Ge and GeSn nanowires have been unveiled [16][17][18][19][20][21][22][23] . Temperature-dependent photoluminescence from an ensemble of vertically grown nanowires revealed the direct bandgap nature of GeSn nanowires with a high Sn contents up to ~ 19 at% 19,20 .…”

Section: Introductionmentioning

confidence: 99%

Strong extended SWIR cavity resonances in a single GeSn nanowire

Kim

Assali

Joo

et al. 2022

Preprint

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Nanowires are promising platforms for realizing ultra-compact light sources for photonic integrated circuits. In contrast to impressive progress on light confinement and stimulated emission in III-V and II-VI semiconductor nanowires, there has been no experimental demonstration showing the potential to achieve strong cavity effects in a bottom-up grown single group-IV nanowire, which is a prerequisite for realizing silicon-compatible infrared nanolasers. Herein, we address this limitation and present the first experimental observation of cavity-enhanced strong photoluminescence from a single Ge/GeSn core/shell nanowire. A sufficiently large Sn content (~ 10 at%) in the GeSn shell leads to a direct bandgap gain medium, allowing a strong reduction in a material loss upon optical pumping. Efficient optical confinement in a single nanowire enables many round trips of emitted photons between two facets of a nanowire, achieving a narrow width of 3.3 nm. Our demonstration opens new possibilities for ultrasmall on-chip light sources towards realizing photonic-integrated circuits in the underexplored range of extended SWIR.

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Growth mode control for direct-gap core/shell Ge/GeSn nanowire light emission

Cited by 23 publications

References 40 publications

Oxide Decomposition and Sn Surface Segregation on Core/Shell Ge/GeSn Nanowires

Oxide Decomposition and Sn Surface Segregation on Core/Shell Ge/GeSn Nanowires

Impact of strain engineering and Sn content on GeSn heterostructured nanomaterials for nanoelectronics and photonic devices

Strong extended SWIR cavity resonances in a single GeSn nanowire

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